1 files changed, 92 insertions, 0 deletions
diff --git a/browser/components/webextensions/ext-sessions.js b/browser/components/webextensions/ext-sessions.js
new file mode 100644
index 000000000..4c13a1ac3
--- /dev/null
+++ b/browser/components/webextensions/ext-sessions.js
@@ -0,0 +1,92 @@
+/* -*- Mode: indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim: set sts=2 sw=2 et tw=80: */
+"use strict";
+
+Cu.import("resource://gre/modules/ExtensionUtils.jsm");
+var {
+  promiseObserved,
+} = ExtensionUtils;
+
+XPCOMUtils.defineLazyModuleGetter(this, "SessionStore",
+                                  "resource:///modules/sessionstore/SessionStore.jsm");
+
+function getRecentlyClosed(maxResults, extension) {
+  let recentlyClosed = [];
+
+  // Get closed windows
+  let closedWindowData = SessionStore.getClosedWindowData(false);
+  for (let window of closedWindowData) {
+    recentlyClosed.push({
+      lastModified: window.closedAt,
+      window: WindowManager.convertFromSessionStoreClosedData(window, extension)});
+  }
+
+  // Get closed tabs
+  for (let window of WindowListManager.browserWindows()) {
+    let closedTabData = SessionStore.getClosedTabData(window, false);
+    for (let tab of closedTabData) {
+      recentlyClosed.push({
+        lastModified: tab.closedAt,
+        tab: TabManager.for(extension).convertFromSessionStoreClosedData(tab, window)});
+    }
+  }
+
+  // Sort windows and tabs
+  recentlyClosed.sort((a, b) => b.lastModified - a.lastModified);
+  return recentlyClosed.slice(0, maxResults);
+}
+
+function createSession(restored, extension, sessionId) {
+  if (!restored) {
+    return Promise.reject({message: `Could not restore object using sessionId ${sessionId}.`});
+  }
+  let sessionObj = {lastModified: Date.now()};
+  if (restored instanceof Ci.nsIDOMChromeWindow) {
+    return promiseObserved("sessionstore-single-window-restored", subject => subject == restored).then(() => {
+      sessionObj.window = WindowManager.convert(extension, restored, {populate: true});
+      return Promise.resolve([sessionObj]);
+    });
+  }
+  sessionObj.tab = TabManager.for(extension).convert(restored);
+  return Promise.resolve([sessionObj]);
+}
+
+extensions.registerSchemaAPI("sessions", "addon_parent", context => {
+  let {extension} = context;
+  return {
+    sessions: {
+      getRecentlyClosed: function(filter) {
+        let maxResults = filter.maxResults == undefined ? this.MAX_SESSION_RESULTS : filter.maxResults;
+        return Promise.resolve(getRecentlyClosed(maxResults, extension));
+      },
+      restore: function(sessionId) {
+        let session, closedId;
+        if (sessionId) {
+          closedId = sessionId;
+          session = SessionStore.undoCloseById(closedId);
+        } else if (SessionStore.lastClosedObjectType == "window") {
+          // If the most recently closed object is a window, just undo closing the most recent window.
+          session = SessionStore.undoCloseWindow(0);
+        } else {
+          // It is a tab, and we cannot call SessionStore.undoCloseTab without a window,
+          // so we must find the tab in which case we can just use its closedId.
+          let recentlyClosedTabs = [];
+          for (let window of WindowListManager.browserWindows()) {
+            let closedTabData = SessionStore.getClosedTabData(window, false);
+            for (let tab of closedTabData) {
+              recentlyClosedTabs.push(tab);
+            }
+          }
+
+          // Sort the tabs.
+          recentlyClosedTabs.sort((a, b) => b.closedAt - a.closedAt);
+
+          // Use the closedId of the most recently closed tab to restore it.
+          closedId = recentlyClosedTabs[0].closedId;
+          session = SessionStore.undoCloseById(closedId);
+        }
+        return createSession(session, extension, closedId);
+      },
+    },
+  };
+});